NASHVILLE — On Thursday morning, The Knoxville News Sentinel published a front-page story by Matt Lakin about the imminent execution of Billy Ray Irick. The inmate had been on death row since 1986, a year after he confessed to raping and murdering a 7-year-old child left in his care. The little girl was named Paula Dyer. She called her murderer “Uncle Bill.” The print headline read, “Paula Dyer’s last day on Earth.”

Thursday was Billy Ray Irick’s last day on Earth. His execution was the first in Tennessee since 2009.

The physical evidence against him was incontrovertible, and no one is questioning his guilt. But there are big questions about whether Tennessee should have executed him. As Nashville Scene’s Steven Hale has reported in depth, Mr. Irick apparently suffered from severe mental illness. He spent much of his childhood in a home for abused and troubled children. He told people the devil was giving him orders. He chased another little girl down the street with a machete.

Based on post-trial affidavits from Paula Dyer’s stepfamily, the psychologist who pronounced Mr. Irick fit to stand trial in 1986 later questioned that judgment. “Is he fit for execution? That combination of words,” Mr. Hale writes, “like so many in the lexicon of the death penalty, twists the English language into a peculiar shape. But it is crucial.” In the United States, executing an insane person is unconstitutional.

Another problem with this execution is Tennessee’s new protocol for lethal injection. The first drug administered in an execution is supposed to put the inmate to sleep so he can’t feel the effects of the other two drugs: the one that causes paralysis and the one that stops the heart. But midazolam, the sedative in Tennessee’s execution cocktail, doesn’t always render complete unconsciousness. It’s possible for the inmate to feel the effects of the next two drugs, and what he feels is akin to being suffocated and burned alive at the same time.

The United States Supreme Court had declined to delay the execution, but Justice Sonia Sotomayor strongly dissented: “In refusing to grant Irick a stay, the court today turns a blind eye to a proven likelihood that the state of Tennessee is on the verge of inflicting several minutes of torturous pain on an inmate in its custody,” Justice Sotomayor wrote. “If the law permits this execution to go forward in spite of the horrific final minutes that Irick may well experience, then we have stopped being a civilized nation and accepted barbarism.”

This is the unvarying pattern in death-penalty cases: arguments in favor of lenience, arguments in favor of severity and a perfectly realistic assumption that nothing at all will change. Some victims will be more sympathetic than others. Some death-row prisoners will be harder to hate. Defense attorneys will point out extenuating circumstances. Critics will list the pragmatic arguments against the death penalty — from its failure to deter crime to the racial disparities in its application to its terrifying permanence.

It would be a tiresome litany if not for the fact that a human life hangs in the balance. It would be a tiresome litany if not for the fact that in state executions, the executioner is always you.

Plenty of people are happy to play the role of public executioner. A recent poll from the Pew Research Center found that 73 percent of white evangelical Christians supported the death penalty in cases of murder. Even among Catholics, 53 percent believe capital punishment is an appropriate response to a crime like Mr. Irick’s. This is a curious position, coming from people who drive cars bearing “Choose Life” bumper stickers. It is especially curious considering Pope Francis’s recent unequivocal condemnation of the death penalty. “The death penalty is inadmissible because it is an attack on the inviolability and dignity of the person,” the Catechism of the Catholic Church now reads. That dignity “is not lost even after the commission of very serious crimes.”

Then too, there is the matter of our own dignity, the dignity of those of us in whose name and for whose “protection” the state has decided — in cold blood, with calm premeditation — to take a human life. We are not doing it out of fear or rage or insanity. We are doing it out of a primitive need for vengeance.

Paula Dyer was a beautiful little girl who deserved a full and happy life, but Billy Ray Irick’s death didn’t give it back to her. His death did not erase her terrible suffering or bring her back to the people who have mourned her loss for more than three decades. Justice Sotomayor is right. We are not a civilized nation. We aren’t even close.

Margaret Renkl is a contributing opinion writer who covers flora, fauna, politics and culture in the American South.